Obesity and its resultant complications represent a major public health; further understanding of the underlying pathophysiology will aid the development of preventive and therapeutic modalities. As a pediatric endocrinologist, the P.I. Dr Shah has a committed interest in studying the early mechanistic processes involved in obesity-related metabolic dysregulation, with the hope of exploring novel preventive and treatment options. Her ultimate career goal is to become an independent translational researcher in the field of endocrinology, with a focus in obesity and adipose tissue biology across the pediatric and adult age spectrum. Through her current work with her mentor and training in the Masters in Translational Research program, she has developed essential skills and experience in clinical and translational research. This will allow her to perform the work proposed in this application, which integrates a human clinical trial with studies in human tissues and cells to explore novel pathways in obesity-related adipose inflammation. To acquire further expertise and knowledge as she transitions to independence, Dr Shah has devised a comprehensive career development plan that takes full advantage of the rich research, educational, and collaborative environment at the Children's Hospital of Philadelphia and the University of Pennsylvania. Dr Shah's career plan includes strong mentorship in translational research, didactic coursework in genetics, immunology, and bioinformatics, focused training in necessary laboratory skills and aspects of clinical research, scientific enrichment and professional development through attendance of intra- and extra-mural, seminars and conferences, and clearly delineated steps to independence. She has the full support of the Department of Pediatrics and Division of Endocrinology to ensure adequate time and resources for this training. Additionally, she will receive guidance through her mentors, Dr Muredach Reilly and Dr Karen Teff, and a carefully selected advisory committee of experts in critical areas of her proposed research. In order to complete her proposed studies, Dr Shah will have access to resources in the Penn/CHOP CTSA-sponsored Clinical and Translational Research Center (CTRC), Dr Reilly's laboratory, core facilities, and statistical expertise. Through the completion of the research and educational plans outlined in this application, Dr Shah will gain the experience necessary to establish an independent translational research program exploring mechanisms in obesity across the adult-pediatric spectrum. Murine long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) are used clinically to treat dyslipidemia and are demonstrated in pre-clinical cell and rodent models to decrease adipocyte and monocyte inflammation and prevent adipose leukocyte infiltration during high-fat feeding; in vivo human data, however, is lacking. A key driver of adipose inflammation and macrophage infiltration is adipochemokine signaling, including the CCL2-CCR2 and CX3CL1-CX3CR1 pathways. Whether LC n-3 PUFA anti-inflammatory actions in adipose are mediated via these chemokine systems is suggested by decreased CCL2 levels in mice fed n-3 PUFA but has not specifically been explored, The mechanisms by which LC n-3 PUFA exerts anti-inflammatory effects in adipose are also not clearly defined. Recently a LC n-3 PUFA receptor, GPR120, has been identified that in mouse and cell models appears to modulate n-3 PUFA inhibition of nuclear factor kappa beta (NF signaling to decrease inflammation in cells and adipose tissue. In humans, loss of function of GPR120 confers increased risk of obesity. Together these findings suggest a potential mechanism by which LC n-3 PUFA attenuates obesity- related adipose inflammation. We hypothesize that LC n-3 PUFA modulate adipocyte-macrophage chemokine signaling (CCL2-CCR2 and CX3CL1-CX3CR1) to decrease systemic and adipose inflammation via GPR120 inhibition of NF- B signaling. This application addresses the following hypotheses: 1) LC n-3 PUFA treatment of primary human adipocytes in vitro suppresses chemokine-induced adipocyte inflammation and adipocyte-monocyte interactions via GPR120 2) LC n-3 PUFA treatment of human monocytes and macrophages in vitro modifies CX3CL1-CX3CR1 and CCL2-CCR2 to reduce the inflammatory state of these leukocytes and resultant interactions with adipocytes in a GPR120-dependent manner and 3) treatment of obese human subjects with the n-3 PUFA supplement Lovaza, compared to placebo, regulates the CX3CL1-CX3CR1 and CCL2-CCR2 chemokine systems to reduce inflammatory leukocyte recruitment into human adipose. In vitro studies in primary human cells will assess effects of individual n-3 PUFAs and GPR120 agonists on baseline and inflammatory stimulated chemokine signaling, CX3CL1-CX3CR1 and CCL2-CCR2 induced monocyte-adipocyte adhesion and migration, and.NF activation. Knockdown of GPR120 and NFkB will be used to determine whether anti- inflammatory effects are modulated by these pathways. For the clinical trial, obese, non-diabetic subjects will be treated for 8 weeks with Lovaza or placebo; visits are planned at baseline and 8 weeks for assessment of insulin sensitivity, adipose and blood chemokine levels, NF signaling factors, and adipose and circulating CX3CR1- and CCR2-expressing macrophage and monocyte quantification via flow cytometry.